Read this:

Ethical copyright considerations:

Interesting website and point of view about Digital Ownership vs Copyright:

http://wiki.mkis.edu.my/w/page/13478981/Digital%20Ownership%20and%20Copyright

Royalty free clipart that doesn't require copyright permission:

http://office.microsoft.com/en-nz/images/

Creative Commons Website in NZ - has published work creators hve given authority to make use of, with conditions:

http://www.creativecommons.org.nz/